Biodiversity and pizza – an extended analogy leading to a call for a more multidimensional treatment of nature

I’ve been thinking a lot lately about the term biodiversity. Not so much its scientific defintion as its usage in public discussions. No doubt this is because I am increasingly using the word biodiversity to describe my own work as I move in more applied directions. And a few weeks ago I got to spend over an hour with a reporter talking about the history and implications of using the term biodiversity. She asked good questions and forced me to get clear about what I really think. So I’ve got a lot of thoughts rattling around in my brain on the usefulness of term “biodiversity” that I would like to discuss with the community.

Biodiversity is a really important term that is being woven into the international regulatory framework at the moment. But biodiversity is also an emotion laden term in ecology these days. So … I’m going to adopt the philosopher’s trick and talk about something completely different for a bit (pizza!) and then circle back and tell you I was really talking about biodiversity all along.


Imagine we have some good, some thing, in mind that we passionately believe is excellent and the world needs more of it and and that the world generally needs to get busy paying attention to it. This could be books, it could be food in general. For many it could be coffee or wine (or for ecologists beer). For me it is going to be pizza.

So the first thing I want to look at is what do I mean when I say we need “more” pizza. I would argue there are at least three different senses of “more” that could be relevant:

  1. Absolute quantity – I probably literally want more pizzas in the world. This could be measured directly by counting the number of pizza pies or the total kilograms of pizza produced per day. It might also mean pizza availability in every corner of the world, measured by say 100 km x 100 km pixels in which pizza is sold.
  2. Diversity of types – one of the reasons I love pizza is how diverse it is. There’s New York/Boston pizza with a thin crust and cheese so thick you need a chisel (and lots of napkins to soak up the grease), there’s west coast pizza with an inch of toppings, there’s Chicago deep-dish pizza, there’s true Italian pizza with sparing doses of everything but scrumptious ingredients and a crunchy crust. There’s Hawaiian (my favorite), there’s pepperoni. You can even start playing with the sauce and do barbeque Thai chicken, or pesto and four cheeses. I love the diversity of pizza! We could quantify this by counting the total number of toppings offered on menus or doing a Shannon-Weiner index on pizza styles (e.g. pChicago=0.10).
  3. Quality – If I want the “pizza-ness” of the world to increase I probably want overall pizza quality to increase too. I’m not going to be happy if my efforts mostly result in frozen cardboard pizzas taking over the world. This one is tricky because while there are probably some universally agreed upon dimensions to quality (fresh>frozen), there are also a lot of personal preferences. I love Hawaiian but I have at least two friends who tell me that putting pineapple on a pizza is evil (their words, not mine). And there are people who won’t touch deep dish pizza and people who will only eat deep dish. We can’t really quantify this one. Its too subjective. All we can do is quantify what is available now and and what used to be available.

The second thing I want to look at is now imagine I have taken my pizza love into genuine activism and have started lobbying the world for more pizza. I’ll probably mostly talk to governments and corporations. It won’t be long until I hit a politician or a company boss who looks me in the eye and tells me that I’m crazy, hamburgers are a much more basic and popular food than pizza. Now I have a big choice to make. Do I stick with my basic inherent belief that pizza is good and that much of the world loves pizza (even if some hate it). That between the passionate supporters of pizza and the silent majority that have positive if weak feelings, I can carry the day for more pizza. Or should I start talking about how useful pizza is because it has all four food groups in one food (at least before the US government redefined the food groups), that the anti-oxidants in tomato sauce are very healthy, that pizza is very practical since it can go from the school cafeteria to gourmet restaurants and does OK (compared to other foods) at being kept warm for a while. And etc. In short do I move beyond pizza is good into pizza is practical? or stick with pizza is good and start showing mouth-watering pictures of a steaming, chewy slice of pizza?

The three important questions

Since I tipped my hand so strongly at the beginning, you have probably already figured out that I could repeat the whole discussion replacing the word “pizza” with the word “nature” or even “biodiversity”. Now I want to leverage the analogy to pose three main questions.

  1. Of the 3 aspects of “more” (total quantity, diversity, quality or type) which ones should we emphasize in the public sphere? Indeed which ones are most important?
  2. Is the word “biodiversity” more analogous to “pizza” or “pizza diversity of types”? In other words is biodiversity a generic concept that captures our warm fuzzy feeling about nature (and ultimately all 3 aspects of “more”)? Or is it a much more specific term that is truly only about diversity of pizza types/species (and genes etc) and ignoring quantity and quality?
  3. Was I better off when I ran into opposition switching to a utilitarian argument (“pizza is healthy”, “biodiversity provides ecosystem services”) or sticking to my guns and knowing I had a good brand that polled well and just selling my concept (be it pizza or biodiversity)?

These three questions are, I believe, fundamental questions facing people advocating for biodiversity right now. And there is a lot of disagreement on the answers. I will give my own personal answers in a minute. But let me also emphasize that most of what I am about to say is necessarily opinion and intelligent people will disagree (sometimes strongly). Short of changing the course of entire public discussions in a controlled experimental fashion there is no way to objectively determine who is right and wrong. So I could easily be wrong. But the current approach to public discussion could also easily be wrong. My main goal of this post is not to win the day for my opinions,  but just to at least clearly pose the right questions and start a conversation about them.

Go ahead and take a minute to actually think about and answer these 3 questions for yourself. I’m arguing they’re fundamental. You really should have an opinion …

I’ll wait …

My answers to the 3 questions

My own answers are:

  1.  Which aspect?: all of them of course. There is no reason to pick only one. They are all key components. Per question #2, I’m not quite sure whether the word biodiversity was intended to specialize on just the diversity aspect or not, but it has had that effect and it is unfortunate. If we only cared about biodiversity sensu strictu, at its logical extreme we could just build a super-zoo and be done with it. The degree to which that would be unsatisfying shows pretty clearly that we care about the other aspects (i,e. quantity and quality) as well..
  2. Biodiversity as a generic good or specifically diversity?: I honestly don’t know. It has been a strength and a weakness of the term that it has both connotations. I am really on the fence on what should be used going forward. Biodiversity is really strongly tied to the narrower concept of diversity these days, and it is hard to miss that this is in the name. But biodiversity has a lot of momentum including the UN Convention on Biodiversity and the ensuing IPBES (Intergovernmental Panel on Biodiversity and Ecosystem Services). But terms like nature and wildlands worked well in the 1970s. Ultimately I am going to waffle on this one.
  3. Keep ecosystem services or sell nature for nature’s sake?: Again, why choose? Both utilitarian and aesthetic/spiritual arguments make a lot of sense. Although I do think the pendulum has swung way too far to the utilitarian/ecosystem services side, and thus I would advocate for an increase again in advocating nature for its own sake. But ultimately the answer has to be “all of the above.”

So in short, I am arguing the public discussion about how humans are impacting nature, about what aspects of nature needs to be preserved and why nature needs to be preserved, needs to be an all included approach (quantity, diversity, quality, utility, for its own sake), not to pick a more limited approach (e.g. diversity and utility only or primarily). My opinion is hardly original or isolated (e.g. papers by McCauley, or history of ideas by Mace), but it is a bit out of step with my sense of the current prevailing paradigm which seems to me to primarily justify conservation by invoking only ecosystem services and biodiversity sensu strictu (i.e. just diversity of species) (e.g. paper by Cardinale). It is worth noting that all 3 of those papers were published in Nature so I’m hardly claiming my view is censored. But the Cardinale paper attracted 1083 citations and the McCauley paper only 447 despite the McCauley paper having been around 3 times as long (or in other words McCauley is cited about 50 times/year, Cardinale et al 300 times/year). But this prevailing view of diversity and ecosystem services leaves three  dimensions of nature (quantity, quality, and innate value of nature off the table). And I think that is regrettable.

I respect that there are diverse opinions. I don’t think the other scientists are wrong. And questions centered on biodiversity and ecosystem are very interesting scientific questions (I put a lot of energy into the first one myself). And I don’t think anyone’s motives are at question here. But questions of how best to assess human impact on nature and to advocate for nature are too important to sweep under the rug. Or to have an orthodoxy. Or to shut down conversation for fear the public is watching.

My two-pronged logic for my answers to the 3 questions

My reasoning for my answers to the three questions is two-fold.

First, I have a practical problem. The science doesn’t support only focusing on diversity and ecosystem services. Consider the salt marsh. It is one of the most productive ecosystems around. It has a spare beauty that appeals to many people. And it provides an important ecosystem service of regulating flood tides for the human developments on the other side of the marshes from the open ocean. And it is one of the most threatened ecosystems of all (at least in the temperate world). So we should be pouring conservation dollars into it right? Well, actually if our only justifications for nature are ecosystem services and diversity, then no. Salt marshes are startlingly species poor (indeed it is an interesting basic science question – how can such a productive environment have so few species). If we paved over all the large salt marshes of the eastern US we would lose a few (probably less than half a dozen) species of bird, and maybe an invertebrate or two. And maybe a few more stragglers. Not zero loss, and certainly tragic. But if we’re trying to conserve biodiversity sensu strictu, it would have to rate pretty low on the prioritization list. And as far as ecosystem services, lets just plant invasive Phragmites that grows into a dominant monoculture 3x as high as the native cordgrasses and therefore much more effective at flood control and at least as good at other ecosystem services (e.g. nursery to ocean species). In short, if we can’t invoke quality of ecosystem (e.g. which species are living there) and the innate value of salt marshes (that spare beauty I mentioned), maybe we should just be actively planting Phragmites. Ecosystem services and biodiversity are poor justifications for protecting the salt marshes, something that I (and everybody else with an environmental bone in their body) believes is important. This is arguing by anecdote, but the anecdotes are numerous (we could have a good conversation about buffel grass, nile perch, and etc). Limiting our quiver to only two arrows is a bad idea.

Less anecdotally, what do meta-analyses tell us about hanging our hat solely on biodiversity and ecosystem services?  I am now leaving hot water to boiling oil. But I’m going to present my views anyway. This blog is ultimately about conversation. I hope we have a CVIL & FACT-BASED conversation in the comments. In short, there is growing evidence that the main impacts humans are having on nature are on #1 (quantity) and #3 (quality or which species) and not so much on #2 (biodiversity sensu strictu). Specifically, humans are greatly impacting #1 (total quantity- we have modified about 50% of the terrestrial earth for human uses and harvested many organisms such as marine fish to drastically reduced numbers). We are also drastically impacting #3 (i.e. we have changed the composition of communities creating winners and losers – one study found 10% of the species turns over every decade in the average community, Dornelas et al. 2014 (also see Supp & Ernest 2014). But many local communities have changed very little in #2 (true biodiversity=variation) (e.g. Vellend et al 2013; Dornelas et al 2014; Supp & Ernest 2014; Newbold et al 2015*; Elahi et al 2015 but see Murphy & Romanuk 2014**). And even the fear of a “biodiversity crisis” or impending 6th mass extinction is more a projection about what could happen than something that has already happened (documented extinctions since 1500 in the two best known groups are 129 extinctions out of ~10,000 species for birds and 61 out of ~5,500 for mammals or around 1% in 500 years with only 6/9,900 and 3/5,400 or around 0.05% in 500 years if you exclude evolutionarily isolated islands***  which you should probably do if you’re going to extrapolate – see Briggs).

To be clear, am I saying humans aren’t having a negative impact on nature? No. I definitely believe humans are drastically changing the face of nature to something unrecognizable. And I am very disturbed by that. I just think that the picture using only diversity and ecosystem services is much more mixed than if we look at all five dimensions. Which is why I think we should focus on all five dimensions.


Google N-gram relative usage of different words capturing nature's value.

Figure 1 – Google N-gram relative usage of different words capturing nature’s value. Generic terms like “nature” and “environment” come out much higher than technical terms like “biodiversity” or “ecosystem function”.

My secondary argument is also a practical one. Advertisers have known for a long time that when you want to influence people, emotions work better than rational arguments. Advertisers focus on fear plus peer (and sexual partner) acceptance. Politicians primarily use a mix of fear and hope. Research clearly shows scare tactics such as the gruesome pictures on cigarette packages in much of the world work much better than telling you the odds of getting cancer or a shortened lifespan. Physicists and astronomers have sold billion dollar projects such as the Large Hadron Collider and the Hubbell telescope primarily by focusing on emotional sells like the frontier, the unknown, the grandeur. They well know that if they tried to get into a dollar and cents justification, they would lose. Or see what words connect with the general public using Google Ngram (Figures 1 and 2), albeit certainly with a grain of salt. Generic emotional terms like “nature”, “environment” and “ecology” are used most often. Meanwhile, “wilderness” – a quality oriented term is trending up while “biodiversity” (a diversity oriented term) actually peaked in 2002 and is trending down. “Ecosystem services” barely even registers outside the scientific and policy communities. The environmental movement was launched on books like Rachel Carson’s Silent Spring (an emotion-laden quantity and quality argument). And I vividly remember the publicservice ad campaigns in the 1970s focused on emotional impact including a picture of people throwing trash out of a car creating an ugliness followed by a Native American with a tear rolling down his cheek (another emotion laden quality argument). So this is a second reason I think we should get back to selling nature for nature’s sake and not just for ecosystem services. Biodiversity is more in the middle – it touches some emotional buttons (which is part of why it was picked), but it doesn’t touch as many buttons as “nature”, “wilderness”, “environment” or “keep the woods I vacationed in as a kid looking like the woods I vacationed in as a kid”.

From Google N-gram (nature and environment removed to show tends in lower ranked words)

Figure 2- From Google N-gram (nature and environment removed to show tends in lower ranked words)


Can scientists handle talking about quality of nature?

Why aren’t scientists already invoking all five dimensions instead of just ecosystem services and biodiversity? I think it is pretty simple. Scientists are comfortable with things that are clear cut and quantitative. Biodiversity sensu strictu and ecosystem services fit this paradigm (x species, y$ of ecosystem services). We’re also pretty good at talking about quantity (x% of forest converted to second growth, y% of large fish in the sea removed). But nature for nature’s sake and quality (which species should be there) are much more subjective. They are normative (human values), not innately quantitative. This makes us uncomfortable. And it means we don’t have the best/only opinion around. Other people’s opinions are equally valid to those of scientists about whether phragmites or a native salt marsh is more desirable. This loss of quantiative objective tools and having to share the stage with other opinions is uncomfortable for scientists.

But we have to be willing to move into these areas (or alternatively stop saying biodiversity and ecosystem services are the only worthwhile metrics and then let people more comfortable in public policy advocacy on normative issues move into the full five dimensional discussion). Because these quality/quantiaty/nature-for-its-own-sake are often times the biggest kinds of impacts we’re having on nature. There are plenty of examples of an invasive plants that increases biomass and increase ecosystem services and not infrequently even increase diversity. Creating edges (e.g. by roads or forest fragments) can often increase diversity.  The inconvenient truth is that if we only care about how many species are there in our favorite plot of land and are OK with the changes to which species show up, then an awful lot of plots of land are doing just fine thank you. We scientists have to start finding a way to be comfortable talking about what biodiversity we want, not just how much and how many.

Like I said, part of the answer may be to let people who are more comfortable with normative discussions take over part of the conversation. But I do think scientists have a role even when talking about quality and nature for nature’s sake. Simply documenting what changes are happening and how quickly they are changing is an important piece of data in this conversation and that is the kind of simple objective, quantitative conversation scientists are comfortable with. And the answer of how much humans have changed nature in this aspect of quality (who is there) is, in simple technical objective terms, ginormous. And I do believe lots of people care about that.


So to summarize, what has pizza taught us about biodiversity? What do we need to do to better advocate for the pizza (err ecosystems) we love? 

  1. As a scientist, and trying to preserve scientific credibility well into the future, I am very uncomfortable with the logical inconsistencies that only promoting biodiversity and ecosystem function puts me into – namely that often times invaded, heavily changed ecosystems are “better” by those measures and similarly by those measures humans aren’t having much impact on many parts of the planet.
  2. Therefore, we need to expand out from just biodiversity sensu strictu and ecosystem services to a fully multidimensional view of nature that includes quantity, quality and nature for nature’s sake.
  3. To do this, scientists will have to find a way where we’re comfortable in starting and participating in “quality” discussions (which species should be there). How best to do this may vary from scientist to scientist.

What do you think? How can we most effectively advocate for biodiversity? Is biodiversity a useful term or has it outlived its usefulness? Should we be selling ecosystem services too? How about quality, quantity and nature for nature’s sake? Have I at least asked the right questions? As regular readers know, I highly value dialogue, and am in sincere in wanting to have a conversation, including viewpoints different than my own. But the conversation needs to be factual (e.g. citations or examples) and not or argument by bluster and especially not ad hominem  .

* I am aware the authors present their paper as a sign of a major crises, but the fact is it shows that the decline in richness sensu strictu (after controlling for changes in quantity) is about 8% total over 500 years even when you include every parking lot and cornfield in the globe (and as I’ve noted elsewhere still has one serious bias of using large rainforest->cornfield losses in estimating the more common but smaller prairie->cornfield losses), it is hard for me to read this paper as a sign of drastic biodiversity loss
** We could have a long conversation about why this one paper seems to be contrary to the trends everybody else is finding – in my opinion short story is that they set out to measure something different
*** Australia was classified as an island in this analysis – you can debate this, but the overall picture only changes in degree

51 thoughts on “Biodiversity and pizza – an extended analogy leading to a call for a more multidimensional treatment of nature

  1. Blimey, there’s a lot to digest here – like a very, very large pizza* in fact….. 🙂 But seriously, here’s come initial thoughts to get the ball rolling.

    It’ll come as no surprise that I like the word “biodiversity”: I used it for the title of my blog and for my professorship, because it captures a lot about what I value in the natural world, and because it’s a term that I’ve (professionally speaking) grown up with. To my mind it is an umbrella term that can mean different things to different people; some see this as a disadvantage but I think that, as long as we qualify precisely what we are referring to, to use “biodiversity” in a loose way is not a problem. Perhaps an appropriate analogy is with politics: if someone describes themselves as a “conservative” or a “socialist” or a “liberal”, those terms cover huge internal variation and political scope, but it’s not a problem because it broadly describes the beliefs of that individual.

    The salt marsh example that you give is an interesting one because your conclusion (that the low species diversity in these marshes means that they may not be prioritised for conservation) ignores the fact that all of the “official” definitions of biodiversity (e.g. the CBD**) explicitly include diversity of habitats/communities/ecosystems/biomes in a defined geographical area. Thus losing a salt marsh may indeed result in few species being lost, but it would be a significant loss of biodiversity at that higher level if a region has only woodland and grassland in it: in essence you’ve lost one third of your biodiversity because you’ve lost one third of your habitats.

    The pros and cons of valuing ecosystem services are a much bigger argument in some ways and I’m going to point readers to two blog posts, one very recently from Steve Heard which I think is a concrete example that captures a lot of the uncertainties that you’ve described:

    The second is one of mine from last July related to the value of valuing nature, which was prompted by the Costanza et al. update:

    *Sorry Brian, but Hawaiian pizza is a bloody awful variety that should never have been invented; I’m all for biogeographic culinary fusion, but really….!

    **”Biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.”

    • Interesting to note that the first two responses – yours and Mark’s have exactly opposite responses to what biodiversity means (sensu latu or sensu strictu)!

      I did think about the CBD definition including diversity of ecosystems, but I decided I had gone on far too long already! I guess my short thought on that is that you are technically right that it argues for keeping salt marshes. But does it argue for keeping native spartina marshes over phragmites marshes? And does the diversity of ecosystems receive much attention? And how is that operationalized?

      • Conservationists would certainly value the native spartina marsh over the introduced phragmites marsh as there ought to be more species associated with the former than the latter.

        As to how biodiversity s.l. is operationalised – it’s explicit within management/restoration plans for nature reserves where a diversity of habitats is often desirable, e.g woodland plus open rides plus wetland areas. It’s also implicit within things like the Lawton Report in the UK that advocated “bigger, better, more joined up” nature conservation that focused on landscapes rather than just the reserves. We also have what are Biodiversity Action Plans for habitats as well as for species.

      • Jeff – you clearly know more about this than me, but I am still missing how “diversity of ecosystems”argues for spartina marsh over phragmites marsh – you response is that there are more species in spartina is an argument about “diversity of species”, isn’t it? It is true that a phragmites marsh has fewer species than spartina (but its not a huge drop and it gets pretty complicated depending on if you look at plants only or insects or also birds and high marsh only or low marsh too and pretty quickly the change is much clearer as a change in quality than it is in biodiversity)

      • Sorry, I wasn’t clear, I’m actually talking at two different levels: the spartina-phragmites argument relates to species-level biodiversity, as you say. Having said that, if the spartina marsh showed significant zonation and the phragmites marsh did not, that could be an argument at a habitat level.

      • Another nice link.

        I guess for me it is about transparency and clarity. If I’m making a scientific statement I need to wear my scientist hat. But my day job does not require me to call conflict of interest in the voting booth and not vote on environmental issues. Nor to not express opinions in conversations with people. Nor indeed to not write blog posts with opinions.

        I recognize that many would call this hopelessly naive. And there are plenty who would take any advocacy by a scientist as a sign that we should throw out everything they say. But we all have to find our own way through this challenge.

  2. I thought only children preferred Hawaiian pizza. Anyway…

    Thanks for this great provocation to think, Brian. I am one of those scientists uncomfortable with making normative judgments (“which species should be there”) and more generally in blending science and advocacy. Your post hops back and forth between the two, and to me the answer to many questions can depend on whether the goal is to move science forward or to achieve political goals. This, in turn, is the source of my discomfort with the science-advocacy fusion: we might make a decision as advocates that is to the detriment of scientific credibility, and therefore, ultimately (and ironically), to the role that science plays in determining policy. As a scientist, my thoughts on your questions A-C are as follows:

    A. “quantity, diversity, quality…which ones are most important?”. Unanswerable question, without specifying ‘important for what’. One aspect might be important for sucking carbon out of the atmosphere, another for aesthetic and recreational appreciation of nature, and so on.

    B. The only way to keep the term biodiversity scientifically useful is to restrict its use to something involving “diversity” (seems obvious enough to me, given that “diversity” is in the term itself). If biodiversity = nature, scientific studies of nature are also studies of biodiversity, so they’re about everything and therefore about nothing in particular.

    C. Whatever we do as scientists, we just need to be clear about whether our arguments are supported by evidence (that’s why our opinions are considered to “count” in the first place). For example, if we are discussing a rare species of orchid, the “nature for nature’s sake” argument is not scientific (except in the sense that we can estimate how many people (dis)agree), and so my opinion (save the orchid!) counts for no more than anyone else’s just because I’m a scientist. As scientists, we are uniquely qualified to use knowledge gained from many relevant studies to weigh in on the probability (never a certainty) that extinction of the orchid will have an impact on ecosystem services or anything else. We need to be honest about that probability.

    • You are right that the role of scientists vs advocacy is interwoven throughout my post. And scientists are of different minds about that. I recall a conference in Montreal (might have been CEES but I think it was IBS) where this debate went on for some time during the comments section of a talk.

      I am of two minds. On the one hand I wholly agree that our credibility as scientists depends on sticking to scientific facts and being objective (I had a couple of paragraphs on that in one draft of the post but I mercifully deleted them).

      But on the other hand, many scientists do feel called to be advocates. And certainly the whole term biodiversity arose out of just such scientists. And those people are claiming to represent scientists when they do so.

      So in the end, I think whichever view you subscribe to (and I’m good with a diversity of views on this), figuring out what biodiversity means and how we measure human impact on nature is not a debate a scientists studying nature can wholly avoid.

      • And ironically there is now a debate within ESA again about whether we should be doing more or less advocacy than we are.

      • I’m not as in touch with those debates as you. I’m curious whether anyone on the “less” side of the argument ever says “Anyone who wants to be an advocate should go join the Nature Conservancy”.

      • I think this hasn’t happened so much. And my speculation to why is that advocates want to keep their science mantle as a professional science society when advocating. Not go join an NGO that is seen as just another advocacy group. I think that is a really profound issue which threads through the issues Mark raises. And for that matter is very interwoven with the whole genesis of biodiversity. In a great book by David Takacs (recommended to me by Mark) he basically interviews a bunch of the big names (EO Wilson, Soule, etc) and ends up concluding that the term biodiversity was coined exactly because it straddles the scientific domain and the advocacy (at least warm fuzzy attitude towards nature) domain.

        As my answer to Jeff suggests, I think we have to be willing to be clear if we’re wearing a science hat or a personal opinion hat. A lot of people intentionally do the opposite and conflate the two. And I guess that makes me uncomfortable (but not uncomfortable enough to give up one of those hats).

      • Is it not possible to wear both hats simultaneously – advocate/polemicist and scientist – the latter backing up the former?

        I’m unaware as to whether the BES has discussed advocacy and campaigning at a high level, but it certainly takes stands on “issues”, which not all members are happy with – see Simon Leather’s recent post on why he boycotted the BES winter meeting last year:

      • Sure you can. And a lot of people do in this domain of biodiversity. And I’m not saying its wrong. But one shouldn’t be surprised if others (both scientists and non-scientists) perceive us and weigh our words differently if we’re obviously wearing both hats at the same time.

      • @Brian:

        Yeah, intentionally conflating those hats makes me uncomfortable too.

        I’m also worried/disturbed by cases in which people don’t seem to be aware that they *are* conflating them. Say, not recognizing that there are non-scientific value judgments implicit in *any* argument for conservation (just as with any argument for any policy).

        But of course it’s hard to avoid conflating those two hats. Especially because, one big way that *everyone* tries to win debates about values is to debate the facts and their relevance. Often people aren’t even conscious that they’re doing it–but they are. As an extreme but not unrepresentative example, think of how Julian Simon and Paul Ehrlich both claimed that basic “facts” were totally on their side and that the other side was just ignorant:

      • I don’t think that I can agree with you that *any* argument for conservation is a value judgement, Jeremy, because human populations need functioning ecosystems to survive, on at least a global, and frequently a local, scale. It’s hard to argue that that’s a value judgement unless we don’t value human life. I’d agree that the nature of those ecosystems, and what constitutes one that functions, may be a value judgement (or at least up for debate) but that’s a potentially very risky experiment.

      • This has come up repeatedly in council discussions of the CSEE (Canadian Society for Ecology and Evolution) as well. Strong opinions in both directions: don’t mix science and advocacy vs. we’re abdicating our responsibility as ecologists by not “speaking out”. So far CSEE has erred towards not taking on an advocacy role.

  3. Brian, while I hate to trivialise such a long, well thought-out post, I wonder if you might indeed be asking the wrong questions.

    “How can we most effectively advocate for biodiversity? ”
    Well, I am almost 99% sure that this answer depends on who you are trying to convince. We will have to tailor our message to suit the “languages” spoken by the mining, manufacturing or agriculture sectors, for example. Similarly governments will respond to a different message to development aid NGOs. There is no one way to advocate for biodiversity most effectively.

    The follow up questions about whether we should use ecosystems services, quality, quantity or nature for nature’s sake arguments also depends on who it is you are trying to convince. Idealistic undergrads might be swayed by arguing for intrinsic values of nature, but a CEO in the agro-industry will need to hear more about instrumental values if she is going to keep the shareholders satisfied.

    “Is biodiversity a useful term or has it outlived its usefulness?”
    Again, it depends on how it is being used. If biodiversity is used as a synonym for species richness, then NO it is not useful. Why use a fuzzy term to describe something that can be defined using clearer terminology? But if we are using “biodiversity” as a hold-all term for various features of nature (e.g. species richness, phylogenetic distinctness, abundance, population genetics, functional diversity) then the term “biodiversity” actually simplifies communication with non-science stakeholders. I do believe that using the term “biodiversity” in this way requires some initial clarification, but in my limited experience this isn’t too much of a challenge for most people to understand.

    • You are of course right that what is most effective depends on context. That doesn’t eliminate the questions though. It just creates 5 or 10 (or how however many contexts there are) versions of the questions. And those contexts are not totally isolated. I do think it is meaningful to discuss the question in general as well as in specific contexts.

      And to your last paragraph, I’m really enjoying how the first three commenters have such distinctly different views of what biodiversity means (or should mean).

  4. Hi Brian,

    Very interesting and provocative post. However, I can’t help think that an economist reading your post would point to your pizza analogy and say “you seem pretty happy with the current state of pizza with all its dimensions and nuance. And what is responsible for fostering that? The free market, which has created such diversity and dimensions to meet demand.” Rather than think of ‘advocacy for pizza’, which seems to come down to promoting the preferences of some faction at the cost to some other (e.g. emphasizing the health benefits might distort supply against greasy pizza), one should focus on policies that address distortions (pineapple tariffs impacting the supply of Hawaiian pizza, say). Putting a price on pizza does not reduce it to a “single dimension”, but rather allows the diversity to flourish in a world where many people like different pizza quantity, quality, and variety.

    The economist may also point out the flip side of when it is justified intervening to tip the balance of that market solution: when ‘free market’ solution results in tragedy-of-the-commons (or external cost): cheap greasy pizza out-competes healthy pizza with the result that we have worse average health and higher health-care costs. That might lead us to policy of subsidizing healthy pizza (or removing subsidies that make greasy pizza so cheap) for an economic reason, rather than just in response to interest group pressure that prefers a certain outcome. Public goods (health, salt marshes) generally call for different approaches than private ones (like pizza).

    I’m not necessarily saying I espouse these views or that under this more economic picture that we can just swap in biodiversity of pizza and be done with it. But perhaps it is instructive in thinking about a good that different individuals value differently without simply devolving into how can faction A best advocate for their values to take precedence over the values of others?

    • All interesting points Carl. “But perhaps it is instructive in thinking about a good that different individuals value differently” – I think this is exactly why I have such a hard time with boiling nature down to dollars. The amount people are willing to pay is so variable. I’m willing to pay to keep a native salt marsh. A homeowner on the marsh might or might not be willing to pay depending on whether they value the “beauty” or the flood prevention.

      I’m sure one could argue this is exactly what the marketplace is for – to work out these differences and match up people with differing values so that both benefit.

      The problem I have with this is that nature (even if we think of it as say land easements) is not a high volume frictionless market. And it does have a severe tragedy of the commons problem (I benefit if you set aside land for nature) that is easy to call an externality that should be addressed but not so easy to actually address (the list of externalities that are exploited is probably much longer than the list of externalities that have been well addressed). Moreover, nature is not a transportable good, further limiting the marketplace. In short, I think nature is a great example of where the invisible hand fails pretty badly, and so solutions enter the policy arena.

      • A big problem with the whole “willingness to pay” thing is that there’s not actually a market for most of the “ecosystem services” that we’d like to value, and no way to make one. Not just because of market volume or frictions or because some services aren’t transportable, but for all sorts of other reasons, some of them quite deep and (in my view) insoluble. So yes, humans would be much worse off in many ways (including some standard textbook economic ways) if various “natural services” ceased to exist. But the sort of dollar value that certain environmental economists try to put on “ecosystem services” is emphatically not a conventional price and it makes me cringe a little when it seems to be treated as such.

      • Brian (and Jeremy), just to be clear, I think we quite agree about biodiversity, we just disagree about pizza. That is, I don’t find your pizza analogy helpful because I think it is a case where economics works pretty well. Just like you say, the reason this is not so simple with biodiversity goes back to all the ways biodiversity is different than pizza, which you list here but I felt you neglected in your original piece.

        I know very little about economics, but of course it has a lot to say about all these issues of where markets fail and what the role and mechanism government can use to address them. Knowing little about either side, I can only imagine that economists also cringe at the idea of trying to forge ahead with a price on nature — isn’t land use one of the oldest examples of a public good?

      • Carl, you did what all good philosophers do and pushed my analogy far enough until it broke 🙂

  5. Excellent post. An ambiguous, super-generalist term like ‘biodiversity’ means nothing when we are in the habit of defining the world with standardised labels and categorisations. Focusing on context (i.e. the ‘quality’) is more informative than defining rules & standards (i.e. the ‘quantity’), but science tends to focus on the latter. Hence the issues with the ecosystem services term. Yes it has been misused and overused, but the original usage (from Daily’s 1997 book) meaning ‘nature as a life support system’ does not inherently imply dollars or utilitarianism. To me, that phrase absolutely sums up ‘nature for nature’s sake’ – we need nature to be functioning around us to survive, but we don’t necessarily have to be actively involved in controlling or managing those functions. Sometimes, things might not happen in the way we want (e.g. disservices), but if that is a natural part of how that ecosystem functions, how do we prove it’s a ‘bad’ thing? Again, that is a context-laden question…see our latest paper on the issues with labelling species and interactions as ‘good’ or ‘bad’ in an agricultural context:

    Your point number 1 in the Conclusion is critical – sometimes changed ecosystems are ‘better’….so what is ‘better’? Which is exactly why focusing on the idea of ‘quality’ is absolutely fundamental. However, I see that as where the terminology & concepts of ‘ecosystem function’ and ‘services’ (in the non-monetary sense) are useful. As far as advocacy goes, I think the concept of ecological function is an excellent way to advocate and communicate ecology & conservation science – it creates that functional link with nature that many people have lost in an urbanised, technological world (see ). Focusing on function means we focus on doing whatever we have to do (even if that means not doing anything) to ensure an ecosystem functions in the way it should to maintain all the ecological processes and interactions that sustain it. Of course, that is a whole other kettle of ambiguity, which is why we often find it easier to label individual services & disservices and quantify everything. But questions need to move on from what are ‘good’ or ‘bad’ species? or how many species are needed? to how does overall function (the net outcome of all those good & bad species/interactions) change with context, and what do those changes mean for the wider landscape, other interacting communities, or the biosphere generally?

    • Thanks Manu – you raise many good points (and clearly know the origins of ecosystem services better than I do). I like the concept more as you describe it.

      And I especially agree with your point about how humans becoming urbanized creates a profound disconnect from nature (even as it may be helping nature in some other ways). Nobody needs to explain ecosystem services to farmers (or more extremely hunter gatherers).

      If I understand correctly you are agreeing that we should focus on quality but that the quality should be defined in terms of keeping “nature as a life support system”. It seems to me this arguing a more holistic view of ecosystem services?

      If I am understanding your point of view, which in many ways I like, for me the next logical question is what properties of nature do we need to maintain “nature as a life support system”. How much land would still need to be devoted to forest? Actually how few species could we get away with and still have nature keeping humans alive? What other key attributes of nature would we need to maintain to keep humans alive? I don’t know the answers to those questions (nor does anybody else), but I worry that would still leave room for such drastic changes to nature that I would still be very unhappy with those changes.

      Does that make sense? Am I misunderstanding something?

      • Yes, completely agree. I think the holistic view of ES is key to moving it on from the current issues. There has been a lot of focus on quantifying and valuing individual species, goods or services. But, as you say, what properties of an ecosystem (not just ecologically, but also biogeochemical processes) enable those outcomes? I think we need a lot more info on contexts and variation, rather than quantities of species and individuals. So it’s not so much about ‘how much land would need to be devoted to forest’, but more about what type of forest, where in the landscape should it be, and how should it be managed (or not managed).

    • Great comments Manu, and I agree with most of this especially the view that ESs don’t have to be presented in monetary terms, it’s just a useful (though sometimes misunderstood) shorthand.

      However we need a more nuanced view of “urbanisation” because (i) urban areas can support more species than rural areas in some cases (see our work on urban bees for instance); and (ii) urban areas require local ESs too. One of the changes that’s occurring in what has been termed urban ecology is the idea of ecology *for* cities rather than ecology *of* cities. Steward Pickett is a big advocate of this – see:

      A group of urban pollinator researchers have a short note in review in TREE on this at the moment and I think it’s an interesting change of focus.

      • I like the notion of ecology for cities. There is little doubt that cities depend heavily on the nature around them. I also agree there is a lot more nature within cities than we give it credit for. In fact suburbs often have the highest richness of any area in the region (more than cities or less settled lands).

  6. Brian – terrific post. Jeff Ollerton beat me to the punch by dropping a link (in the very first comment) to my own post on ecosystem services, in which I expressed some of the same reservations as yours. I worry that leaning too heavily on that leaves us hoist on our own petard when it turns out there are better ways than conservation to “improve” a given “service”. But I’m distressed because I don’t think there is a single, logically consistent, inarguable reason for conservation – and yet I desperately want us all to do it. Perhaps Falko’s comment is the answer: there is no such single way to advocate, and the job is more complex.

    • I ultimately think the argument for conservation is “just because”. Because its rewarding, because we owe it to our children, and because we have a moral obligation to stewardship of the earth. The problem is that this view does not give scientists a privileged position. And this view is now something somebody can correctly disagree with. But I think we underrate the power of this view. While in no way an environmental historian, I think this is the view that got us all the progress in the 1970s (in the US at least the 1970s were the high point for environmentalism: the endangered species act, clean air and water acts, the first earth day, first major pesticide regulations, EPA, etc – and much of it under a Republican president). Ultimately I don’t think scientists can be successful until we recognize there are other valid viewpoints and engage with those viewpoints at their level instead of always trying to keep it in the science domain where we “own” the answers. I just rewatched the movie “Merchants of Doubt” last night and the anti-science groups are not engaging with us at a scientific level, and at the moment they are winning.

  7. I think a lot of the problems simply stem from greed. People do not inherently identify with nature and therefore many just want to get what they can from our forests and oceans. While some of us want to expand wilderness boundaries and save what species are left, others want to make money via deforestation and over-fishing processes. Little do they care about the birds living in those forests or the range of invertebrates still in our oceans.

    • That point of view is undoubtedly out there. I personally don’t think its a majority. So the question becomes what is the best conversation to have when those viewpoints are represented but not a majority.

    • Um, with respect Mercedes, and without wanting to deny that there are greedy people in the world (there are, obviously), there are a *lot* of reasons besides “greed” why people might not want to preserve some bit of nature, or why people might just not care that much one way or the other about preserving some bit of nature. Frankly, many of those reasons are very good reasons, or at least reasons that deserve some respect. Further, to the extent that “the problem is greedy people” is a misdiagnosis of the problem (say, because the real problem is other motivations, or structural issues having nothing to do with the motivations of individuals), whatever solution you choose to pursue is likely to fail or even be counterproductive. Finally, I suspect that what you call “greed” others might call “making a living”. People who work in the fishing industry, for instance.

  8. This is an extremely complex topic that requires more historical perspective than can be included in a “pizza” analogy and n-grams. The environmental or nature protection movements date from the early 1800s, possibly earlier, and there is an immense literature on this conflict between using nature, preserving nature and the role(s) of human societies.

    For example, this week I just finished reading 500+ pages of statements about why we need to protect “Nature” from an international meeting held in 1931 (IIè Congrès International pour la Protection de la Nature, Procès-Verbaux, Rapports et Voeux, 30 Juin – 4 Juillet 1931 Paris.)

    Sadly, nothing is new in any of the arguments presented today, nor in the solutions being proposed. All of the same causes are discussed at length for the destruction of “Nature” in 1931 as what we invoke today for explaining the “loss of biodiversity”. The substitution of “biodiversity” for “Nature” sounds like something quantitative and quantifiable, but as some of the comments point out, does not. It is a false debate. Fundamentally arguments about how to conserve, manage or preserve the environment remain based on emotional appeals.

    The central problem (or challenge or oversight) is the absence of a means of comparison. Biodiversity indices can be calculated in different places and times, but it’s not any more possible to quantify how one value is “better” than another, than it is to say one type of pizza is “better” than another. You never improve “biodiversity”, “biodiversity” is how diverse life is when you observe it. “Biodiversity” never decreases, but some indicators of biodiversity (like species richness, abundances, number of alleles, or still size of the individuals, …) can increase or decrease, (even not all in the same direction).

    By replacing “Nature” or “community” with “biodiversity” indices in the current debates, it avoids talking about the network of interactions that define ecological units of study in the debate. I really think there is quite a large distance to be covered before ill-defined concepts like “impact”, “services” and ecologically relevant measurements can be compared on the same baseline.

    • Something that’s occurred to me over the last couple of days of reading comments and thinking about the questions that Brian posed is that “nature” and “biodiversity” are not actually synonymous at all. When people say they like “being in nature” or they “value contact with nature”, what they are usually saying is that they enjoy landscapes, seascapes, changes in the weather, being out of doors, etc., things which are not strictly part of what we understand as “biodiversity”.

      Likewise, “protecting the environment” includes a whole set of non-biodiversity related questions and actions such as air and water quality, wastes management, sustainable use of resources, etc., much of which may not directly affect biodiversity at all.

      “Biodiversity” has a specific meaning, as we’ve discussed, even though that meaning can be broadly defined. Which sounds like a contradiction, but it’s not – and reminds me of the title for the Led Zeppelin fanzine – “Tight But Loose” 🙂 I may have to use that for a blog post about this question….

      • A thousand times yes to your first two points.

        So, is it a problem that you’d never know either of those two points was true if you just skimmed the titles of the talks at the ESA meeting?

      • Not sure if it would be a problem, – I’d probably look at the abstracts too 🙂 But seriously, you could ask that question about a lot of words that we use in ecology, or in the sciences more broadly: entropy, kingdom, phylogeny, extinction, blogging, etc. etc. – all can mean different things to different people.

      • Hmm…I don’t think the issue here is words meaning different things to different people. As you just said said, broad and loosely-defined as “biodiversity” often is, nobody ever uses it to mean “being outdoors, outdoor scenery, etc.” or “clean air, clean water, proper sewage disposal, etc.”

      • In that case I’m not sure what your point is, Jeremy, you’ll have to help me here. I thought we were discussing meanings and definitions of words? The use of “biodiversity” in ESA talk titles could well mean slightly different things to each speaker. Have I misunderstood what you were getting at?

      • Sorry Jeff, my bad–I must’ve misread you. I read you as saying something like “What most people value about ‘nature’ or ‘the environment’ is stuff that has nothing to do with ‘biodiversity’, however we define ‘biodiversity’. Which maybe has implications for what ecologists ought to study, and for what values they should appeal to when arguing for conservation.” I take it that’s not at all what you were getting at?

      • Well I was certainly saying the first part of that but I don’t think that it logically follows that ecologists should then change what they study to accommodate those public values.

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